Train telephone system



Mar. 20, 1923.,

1,448,852. W. W. MACFARLANE.

TRAIN TELEPHONE SYSTEM.

FILED APR, 9, 1920. 2 SHEETS-SHEET 2 Patented 311i.2@, 1923..

WILLIAM W. MACFARLANE, OF ELKINS PARK, PENIb ISYLVANIA, .ALSSIGNOR TO MAC- FARLANE COMMUNICATIONS CORPORATION, OF NEW OF NEW YORK.

Application filed April 9,

To all whom it may concern:

Be it known that I, WILLIAM W. MAOFAR- LANE, a citizen of the United States, and a resident of Elkins Park, in the county of Montgomery, in the State of Pennsylvania, have lnvented a certain new and useful Improvement in Train Telephone Systems, of

which the followingis a specification.

The present invention relates generally 1 to systems of train control and is more particularly an improvement on the invention disclosed in application Sen. No. 203378, filed Nov. 22, 1917, now Patent No. 1,389,258.

The main object of the invention is to dispense with the necessity of having a constant current flow in the rails.

The invention consists, broadly, in the provision of a normally incomplete circuit so connected with the line wires and with the 2 traflic rails that it does not bridge the rails,

whereby, when a car enters a block or subdivision of the rails, communication is established between the car and a wayside station. I

Other features will appear as the specification proceeds:

In the accompanying drawings the inven tion is disclosed in several concrete and preferred forms in which Fig. 1 is a diagrammatic view of a system showing one form of the invention.

Fig. 2 is a diagrammatic view of a system showing a modified form of the invention.

1 and 2 indicate line wires and 3 is an auxiliary wire all paralleling the traffic rails 4 and 5. Wayside stations'or central offices 6 are connected with line wires 1 and 2 at suitable intervals, say, of one hundred miles. One rail (4) of the trafiic track is 0 divided by suitable insulation (7 into blocks or sections of suitable length, depending upon the traffic conditions and other circumstances, as will be understood. 8 and 9 indicate two conductors connected with the line wires. 1 and 2, and withrails 4 and 5. A shunt (10) is connected between 8 and 9, said shunt being normally ruptured by armature 11 under the control of magnet 12, Magnet 12 constitutes the core of a transformer winding 13 in inductive relation to winding 14 of' conductor 15. Said conductor 15 is a part of a normally complete circuit formed by conductors 15, rail 5, conductor 16 and conductor 3. 17 indicates a carhav- TRAIN TELEPHONE SYSTEM.

1920. Serial No. 372,440.

YORK, n. Y., A coaroaa'rxon' transformer winding 28, and then flows by way of conductor 29, line wire 2, conductor 9, having transformer winding 13 to rail 4, across car 17 tojrail 5, by way of conductor 8, line wire 1, conductor 30 to key 31, and by way of conductor 32 back to transformer 28. Energization of transformer coil 13 induces a current in coil 14 which flows by way of conductor15, rail 5. Winding 18 on car, conductor 16 and auxiliary wire 3 back to wind-' ing 14. This induces a current in local tele-' phone circuit 19 of the car. The foregoing description of the circuits assumes that the train is traveling from right to left and is in advance of conductor 16 and behind conductor 15, but it will be evident that if the train is in advance of conductor 15 and behind conductor 16, then current flows to or from winding 18 of the train between the conductor 15 in rear of the train and the conductor 16 in front of the train. A speech current genera-ted in the car will be transmitted to the line Wire and coil 28 over the circuits previously described, and, button 24 being now elevated, current will pass from the coil 28 to receiver 33 as follows:

From coil 26 by wire 34 including-receiver 33 to button 24, and thence by conductor 25 back to coil 26.

To give a signal, either audible or visual or both, along the line -of way, means are employed for energizing core 12 sufficiently to attract armature 11 thereby closing shunt 36. This is accomplished by depressing key 31, thereby placing a powerful source of current here shown as a battery 21 in circuit with" line wires 1 and 2, and establishing a.

10 and illuminating light 35 and ringing bell wire 2, and by wire 37 back to battery 21. As previously pointed out, this attracts armature 11 and closes shunt 10. In addition, it will be understood, that car 17 may communicate over the line wires with car 17 in another block or with another car of the same train, but in another block.

As a modification of the invention, auxiliary wire 3 may be omitted, by grounding Wire 15 and rail 5, as shown in Fig. 2.

'I claim: I v

1. A system of the character described comprising line wires, traiiic rails, a source of supply for impressing current on the line wires, a normally incomplete circuit connected to the line wires and connected to but'not bridging the rails, a second and normally complete circuit connected to the same trafiic. rail, transformers in said circuits in inductive relation to each other, a car for completing said first-named circuit by bridging the,rails, and means on the car responsive to current in the second circuit.

2. A system of the character described comprising: a 'wayside station including sending and receiving devices, line wires, traffic rails, a normally incomplete circuit connected to the line wires and connected to but not bridging the rails, a second and normally complete circuit connected to thesame trafiic rail, transformers in said'circuits in inductive relation to each other, a car for completing said first-named circuitby bridging the rails, and sending and receiving deyices on the car in circuit with the track.

3. system of' the character described comprising: line wires, trafiic rails; a source of supply for impressing current on the line wires, a normally incomplete circuit con nected to the line wires and connected but not bridging the traflic rails, a car for completing the circuit by bridging the rails, and means on the car responsive to the current in the rails, a normall 1 open shunt including an armature in said circuit, a magnet in said circuit controlling said armature, and means for sendingan-dmpulse through said circuit to energize said magnet, 'and a signal along the line of waycontrolled by said shun. V.

4. A system of the character described comprising: a wayside station including sending and receiving devices, line wires, trafiic rails, a normally incomplete circuit connected to the line wires and connected to but not bridging the trafiic rails, a car for completin the circuit by bridging the rails, and son ing and receiving devices on the car in circuit with .the track, a normally open shunt including an armature in said circuit, a magnet in saidv c rcuit confor completing the circuit by bridging therails,'and sending and receiving devices on the car in circuit with the track, a normally open shunt including an armature in said circuit, a magnet in said circuit controlling said armature, and means for sending an impulse through said circuit to energize said magnet, and a signal along the line of way controlled by said shunt.

6. A system of the character described comprising: line wires, trafiic rails, a source of supply for impressing current on the line wires, a normally incomplete circuit connected -to the line wires and connected to but not bridging the rails a second and normally complete circuit connected to the g same traflic rail, a normally open shunt in sald first clrcult, transformers 1n sald circuits in inductive relation to each other, one

of said transformers constituting a magnet, an armature in said shunt under the 7 A system of the character described,

line wires, trafiic rails, a normally incom-l pletej'circuit connected to the line wires and connected to but not bridging-the rails, a second and normally complete circuit connected to the same trafiic rail, a normally open shunt in said first circuit, transformers 105 pleting said first-named circuit by bridging 11 the rails, sending and receiving devices on the 'car in circuit with the track, a wayside station including sending and receiving devices connected to the line wires,

means forimpressing a current of sufficient 116 the county ofNew York and State of New 120 York, this seventh da of April, 1920.

' WILLIAM MACFARLANE. 

